Generic Method in C#

Generic methods in C# are methods defined with a type parameter. They allow for the method to be defined with a placeholder for the types it operates on, which can be specified when the method is called. This flexibility makes generic methods a powerful tool in application development, allowing for more reusable, maintainable, and type-safe code. This article explores the concept of generic methods in C# through various examples and explanations.

Generic Method in C# with Example

A generic method is declared by specifying a type parameter in angle brackets after the method name. Here’s a simple example of a generic method that swaps the values of two variables:

public static void Swap<T>(ref T a, ref T b)
{
    T temp = a;
    a = b;
    b = temp;
}

int x = 1, y = 2;
Swap(ref x, ref y);
Console.WriteLine($"x: {x}, y: {y}"); // Outputs: x: 2, y: 1

C# Generic Method Where T

You can apply constraints to type parameters in a generic method using the where clause. This specifies conditions that the arguments must satisfy. For example, you might require that a type implements a specific interface:

public static void Print<T>(T item) where T : IComparable
{
    Console.WriteLine(item.ToString());
}

C# Generic Method Return Type

Generic methods can return values of the generic type, allowing for flexible return types based on the input types:

public static T Max<T>(T a, T b) where T : IComparable<T>
{
    return a.CompareTo(b) > 0 ? a : b;
}

C# Generic Method Where T Multiple Types

It's possible to specify multiple constraints on a generic type, either different interfaces or a combination of classes and interfaces:

public static void Display<T>(T item) where T : class, new(), IComparable<T>
{
    Console.WriteLine(item.ToString());
}

C# Generic Constraints

Constraints on generic methods allow you to specify that a type parameter must inherit from a particular class, implement a specific interface, or meet other requirements defined by the following keywords:

• class - The type argument must be a reference type.
• struct - The type argument must be a value type.
• new() - The type argument must have a public parameterless constructor.
• base class name - The type argument must inherit from the specified base class.
• interface name - The type argument must implement the specified interface.

public static void Initialize<T>(T item) where T : new()
{
    // This ensures T has a parameterless constructor
    T instance = new T();
    Console.WriteLine("Instance created");
}

Generic methods in C# enable developers to write flexible and reusable methods that work with any type, while still preserving the strong typing of the language. They are particularly useful in libraries and frameworks where operations need to be performed on a variety of types without knowing the specific type beforehand.